Applying Digital Technologies Beyond Design Life

2021 ◽  
Author(s):  
Luiz Paulo Feijo ◽  
Suqin Wang ◽  
Christiane Machado
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Digital Technology ◽  
Predictive Analytics ◽  
Life Extension ◽  
Structural Behaviour ◽  
Structural Evaluation ◽  
Design Service Life ◽  
Remaining Fatigue Life ◽  
Extension Process

Abstract This paper focuses on Floating Production Installations, which are assets designed based on site-specific environmental conditions to determine their design service life. The longevity of these assets depends on the fatigue aspects related to the structural elements and mooring systems. Among the challenges involving the continued services of ageing assets is the integrity of these elements. When an asset reaches its end of design service life, Operators often decide to undergo a life extension process for safe continued operations. Alife extension process generally includes three phases: investigation, determination and implementation. Following a baseline inspection to determine the present conditions of the structures, engineering assessments are to be carried out to evaluate the fatigue damage through the lifecycle of the installation and therefore determine the remaining fatigue life. Collecting information to execute these assessments is challenging and can be automated with the use of digital technology. Digital tools allow an accurate collection of data, providing a continuous evaluation of the remaining fatigue life and supporting an informed decision-making process. Observing the operation of several aging assets and their structural behaviour, the parameters to be measured during the installation's lifecycle have been identified along with other aspects that also contribute to the determination of its continued service. The recommended data acquisition for relevant measurements is summarized in this paper. The application of sensors and monitoring systems on the installations allows measuring these parameters on a continuous basis, and consequently, Operators are able to determine the degradation pattern that the structure is subject to. An estimation of the remaining fatigue life can be achieved by using predictive analysis, which, along with insights of the future expected corrosion, provides Operators the necessary basis to implement corrective measures and mitigations to avoid the occurrence of a failure. This paper offers an innovative, forward-looking technology that allies physics-based processes with digital technology, supported by predictive analytics and continuous structural evaluation, to assess the integrity of an offshore asset in support of safe continued services.

scholarly journals Numerical Evaluation of Structural Safety for Aged Onshore Wind Foundation to Extend Service Life

2020 ◽  
Vol 10 (13) ◽  
pp. 4561
Author(s):  
Youn-Ju Jeong ◽  
Min-Su Park ◽  
Sung-Hoon Song ◽  
Jeongsoo Kim
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Safety Evaluation ◽  
Life Extension ◽  
Structural Safety ◽  
Material Strength ◽  
Design Strength ◽  
Onshore Wind ◽  
Service Period ◽  
Service Life Extension

In this paper, for the case of “service life extension” with the same capacity for wind turbines, a structural safety evaluation was carried out to determine whether to extend the service life of the aged foundation. As a result of this study, it was found that the aged foundation satisfies the structural safety of material strength, ultimate strength, fatigue life, and serviceability up to the present. Although the in-service period has been over 16 years, it has been shown that the material properties of concrete have exceeded the design strength, and no significant material deterioration has occurred. Also, structural safety could be evaluated more realistically based on actual concrete properties. In particular, it has been shown that it has a fatigue life of 40 years or more, so service life can be extended. It is expected that the methodology used in this paper will be useful not only for structural safety evaluation of the foundation in service, but also for decision-making for extending the service life. Furthermore, a more technical approach should be explored by many researchers in the future.

Service fatigue life and service calendar life limits of aircraft structure: aircraft structural life envelope

2016 ◽  
Vol 120 (1233) ◽  
pp. 1746-1762 ◽  
Author(s):  
Y. He ◽  
C. Li ◽  
T. Zhang ◽  
J. Liu ◽  
C. Gao ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Life Prediction ◽  
Residual Life ◽  
Prediction Method ◽  
Life Extension ◽  
Aircraft Structure ◽  
Structural Repair ◽  
Service Life Extension ◽  
Service Environments

ABSTRACTThe service life of aircraft structure includes the fatigue life and calendar life. The Aircraft Structural Life Envelop (ASLE) is a safe and reliable life scope of aircraft structures in service. The specific steps to establish the ASLE are developed, and a residual life prediction method for aircraft structure under service environments is established by combining the ASLE with the Miner theory. Furthermore, a service life extension method of aircraft structure is proposed based on a scope extension of the ASLE, including methods based on reliability analysis and structural repair. Finally, an application example of the ASLE is presented.

Fatigue Life Extension of Offshore Structures by Ultrasonic Peening

2011 ◽  
Author(s):  
Luis Lopez Martinez
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Fatigue Resistance ◽  
Structural Integrity ◽  
High Stress ◽  
Offshore Structures ◽  
Life Extension ◽  
Original Design ◽  
Ultrasonic Peening ◽  
Offshore Installations

The service life of offshore installations is limited by its structural integrity. Furthermore the structural integrity is mainly governed by the fatigue resistance of critical welded details. In a FPSO installation these details are among others pallet stools weld joints to deck structure and bulkheads/web frames weld connections to longitudinal in ballast tanks. ultrasonic peening can improve the fatigue resistance of welded joints. Fatigue test results shows an increase of four times for high stress ranges and up to ten times for high cycle fatigue. For specimens which have already consumed half of their fatigue life the treatment resets the clock to zero, as a minimum value. Consequently ultrasonic peening treatment was applied to several offshore installations on fatigue sensitive weld connections with the objective to extend the service life of the these. Finite Element Analysis carried out by classification societies for these offshore structures demonstrated critical fatigue lives for several weld connections. These weld connections were then treated by ultrasonic peening with the objective to extend their fatigue lives and by doing that reach the targeted service life for the installation. The successful application of the ultrasonic peening treatment was a pioneering work which involved several partners. A pilot project on a FPSO started in 2005 and the treated critical weld connections are still intact and show not sign of crack initiation despite the fact the calculations then showed shorter fatigue lives than the life span already consumed. As a result the same ultrasonic peening procedure has been proposed to be applied for other fatigue sensitive locations on the installation. Offshore installations around the world are reaching their original design life. Most of the operators chose to extend the service life of their assets rather than scrape them and build new. The reasons for that are: improved oil recovering techniques, time required to get a new build installation on site, environment concerns, wiser management of energy and resources among others. Therefore the Life Extension of Offshore Installations is a subject of current interest for the upstream industry.

Fatigue Tests on Corroded Mooring Chains Retrieved From Various Fields in Offshore West Africa and the North Sea

2019 ◽  
Author(s):  
Kai-tung Ma ◽  
Øystein Gabrielsen ◽  
Zhen Li ◽  
David Baker ◽  
Aifeng Yao ◽  
...  
Keyword(s):  
Fatigue Life ◽  
West Africa ◽  
North Sea ◽  
Test Procedure ◽  
Fatigue Tests ◽  
Surface Feature ◽  
Life Extension ◽  
Mooring System ◽  
Remaining Fatigue Life ◽  
Mooring Chain

Abstract When an aged mooring system seeks a life extension, it is necessary to assess the remaining fatigue life of the corroded mooring chain. This paper summarizes the results of fatigue tests performed on mooring chain samples retrieved from six different fields in West Africa and North Sea. The impacts of corrosion on fatigue life on the samples were researched. The tests were managed under a Joint Development Project, “Fatigue of Corroded Chains (FoCCs JDP)”. The objectives of the JDP are (1) to derive a methodology for assessing the remaining fatigue life of corroded chain, (2) to develop guidance for performing reliable FEA of chain links to assess remaining fatigue life, and (3) to provide more rational basis to improve industry guidance on mooring line replacement criteria for life extension. Fatigue test procedure was defined by the fifteen (15) participating members. The procedure specified the testing parameters, including mean tension, tension range, and test frequency. Six sets of fatigue tests have been completed in seawater with the number of cycles to failure recorded. These chain samples were retrieved from floating production and storage units, e.g. FPSOs and FSUs, that were still in service. Fatigue data obtained from the tests were plotted against the design SN curves and results from fatigue testing of new chain. It was found that most of these samples have limited amount of fatigue capacity remained. Most interesting finding is that the sharpness of the surface feature on the corroded chain link has a significant impact on the remaining fatigue life. Another interesting finding is that the surface feature created by corrosion can be quite distinct and unique depending on the geophysical locations where the sample came from. These findings and test results may serve as references for life extension assessment of an aged mooring system.

General Recommendations From the Results of Reassessment of 21 Platforms in Bay of Campeche

2010 ◽  
Author(s):  
Partha Chakrabarti ◽  
Juan de Dios de la O.
Keyword(s):  
Fatigue Life ◽  
Service Life ◽  
Oil And Gas ◽  
Fatigue Behavior ◽  
Life Extension ◽  
Individual Member ◽  
Inspection Planning ◽  
Natural Period ◽  
Oil And Gas Exploration ◽  
Structural Weakness

Pemex Explorac´ion y Produccio´n (Pemex) owns and operates several fields for oil and gas exploration in the Bay of Campeche located in the south Gulf of Mexico. In order to meet the growing demand for oil and natural gas it was necessary to extend the service life for many existing platforms by at least another 15 to 30 years. To ensure a safe operation throughout this period, thorough and systematic reassessment studies needed to be conducted leading to the identification of any structural weakness. Finally, to control the fatigue behavior of the welded joints, risk based inspection planning (RBI) was adopted to ensure extended service life. In these reassessment studies the ultimate strength of the platforms is evaluated through nonlinear pushover analyses as a part of condition assessment. Spectral fatigue analyses are performed to identify the fatigue sensitive joints. This is followed by redundancy analyses, assuming that one individual member at a time becomes ineffective given a weld fatigue failure at the joint. For the inspections aimed to control the development of predictable degradation such as fatigue crack growth, the inspection efforts can be targeted such that the risks implied by the degradation are kept within acceptable limits. This is done through a risk based inspection planning strategy. The analytical aspects for this approach were discussed in previous papers on the subject by the authors. The current paper presents the overall results of 21 platforms taken up for a recent study and discusses the trends in view of broad parameters such as water depth, loading, structural arrangement. These structures include drilling, production, gathering and living quarter platforms. The platforms are located in various assets in water depths ranging from 40 to 90m, have different configurations with 3, 4 and 8 legged jackets, they also support different deck weights. In the present paper overall results of the study performed for 21 platforms are presented. The platforms have been classified in terms of platform type, number of legs, framing pattern, leg diameter etc. The results for strength of the platforms obtained from pushover analyses, and fatigue life are analyzed in light of the classification parameters. The differences in the platform characteristics such as stiffness, wave loading and natural period are discussed along with their implications to strength and fatigue life. Inspection requirements are also interpreted in the light of these global parameters. Finally, some general recommendations are made for design of jackets keeping in view the overall behavior and inspection requirements. It is believed that if the recommendations are followed in the initial design there would be benefits in the future for inspection, maintenance, and repair and possible life extension increasing their economic return.

Assessment of Offshore Structures for Life Extension

2008 ◽  
Author(s):  
Gerhard Ersdal ◽  
Erik Ho¨rnlund
Keyword(s):  
Service Life ◽  
Continental Shelf ◽  
Offshore Structures ◽  
Design Methods ◽  
Life Extension ◽  
Considerable Part ◽  
Design Service Life ◽  
Extended Life ◽  
Norwegian Continental Shelf ◽  
New Facilities

A considerable part of the structures on the Norwegian continental shelf have passed or are close to the design service life. Several of these structures are planned to be used further in an extended life. In most cases, traditional analyses in accordance with design methods are used for evaluating the structures for life extension. The present regulation and standards have so far had emphasis on design of new facilities, and a need for updated regulations and standards also taking into account ageing facilities and life extension is well overdue. This paper will discuss aspects of ageing that may reduce safety of offshore facilities, maintenance needs for ageing facilities, and propose general principles of assessment of ageing facilities for life extension. The paper is a summary of the research performed by and for the Petroleum Safety Authority - Norway.

scholarly journals Correction: Wang et al. Generalized SCF Formula of Out-Of-Plane Gusset Welded Joints and Assessment of Fatigue Life Extension by Additional Weld. Materials 2021, 14, 1249

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2331
Author(s):  
Yixun Wang ◽  
Yuxiao Luo ◽  
Yuki Kotani ◽  
Seiichiro Tsutsumi
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
Life Extension ◽  
Out Of Plane

The authors wish to revise in the text of Appendix A, pages 19–21 [...]

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